Field of the Invention

The invention relates to the method of manufacturing of elastomer skin especially for interiors of motor vehicles.

Background of the Invention

The elastomer skin is a part of the interior of the motor vehicle because it is used for covering (lining) of external surfaces of interior panels of the body, for instance for instrument panel (dashboard) . The skin is made of thermoplastic elastomer materials by distributing of the elastomer onto a negative metallic mould. The shape of this mould corresponds exactly with the product to be covered with the skin. Thus the products to be covered may have whatever shape, i. e. even such a shape which includes external surfaces which cannot be rolled out into a plain.

Hitherto, the methods used for manufacturing of elastomer skins are based on three different ways of application of the elastomer:

1. By strewing of the powder of thermoplastic elastomer onto the surface of a pre-heated metallic mould where the powder is melted down and creates via sintering a thin layer called skin.

2. By immersing of the surface of a pre-heated metallic mould into a layer of powder of thermoplastic elastomer where the powder is melted down and creates via sintering a thin layer called skin.

3. By spraying of a liquid reaction mixture of components onto the surface of a pre-heated metallic mould where the reaction mixture becomes - via polymerisation process - thermoplastic elastomer {for instance polyurethane-based, see patent No. US 6071619) and creates the elastomer layer called skin. This method enables manufacturing of multi-colour skins.

The first two methods mentioned above enable effective manufacturing of elastomer skin only from one material of one colour. Thus the manufactured skin does have only one colour. These methods are not suitable for manufacturing of multi-colour skins because of too large technological difficulties.

The third method mentioned above, the spraying of liquid reaction mixture, enables spraying of various materials onto the surface of the mould through special masks. The masks cover - in an exact way - the selected areas of the surface of the mould. Consequently the resulting skin can have - on different places - different colours and/or different properties. Nevertheless this method requires a very precise set-up and keeping of technology parameters as well as a more complex production equipment.

Summary of the Invention

The invention refers to the method of manufacturing of elastomer skins which are used for covering (lining) of the surfaces of interior panels of the bodies of motor vehicles.

The method of manufacturing of elastomer skins according to the invention consists in throwing of thermoplastic elastomer powder in solid state and at normal temperature

through a jet onto the surface of a pre-heated negative mould where the elastomer particles stick, melt down and conjoin via sintering and thus create a coherent, thin layer of the elastomer skin. After cooling down the skin adopts the shape and surface texture of the mould.

The mould mentioned above has usually a negative shape and a negative surface texture of the product which shall be covered (lined) with the manufactured skin. The mould must be reliably pre-heated over the interval of melting points of the applied elastomer and it must be treated with a separator. Mostly, the mould is manufactured of a metal but it can be manufactured from another material too.

For throwing of particles of elastomer powder towards the surface of the metallic mould some credible methods of applying of powder polymeric materials can be used, for instance common pneumatic guns possibly supported by electrostatic field. The elastomer powder shall be applied until the required thickness of the skin in particular area is reached. Then the mould with the applied layer shall be left to cool down in order to enable the withdrawal of the manufactured elastomer skin off the mould.

Whatever part of the surface of the mould can be covered or disclosed (protected) with respect to the flying particles of the elastomer powder. Thus not only one material but also some more and various materials can be applied step by step to various places of the mould and consequently a skin can be manufactured which possesses - in different places - different properties, for instance different colours.

The solution according to the invention combines the advantages of the actual methods. It preserves the simplicity and controllability of the manufacturing

process and equipment and at the same time preserves the ability to use the masks in order to apply more than one elastomer material for single one skin. The solution according to the invention can be used for all kinds of thermoplastic elastomers.

Description of the Preferred Embodiment

An example of possible method of manufacturing of elastomer skins according to the invention is the process of manufacturing of elastomer skins made from vinyl thermoplastic elastomer and determined for covering (lining) of external surface of the instrument panel of the motor vehicle.

The metallic mould made of Aluminium alloy has a negative shape of external surface of the instrument panel carrier and the functional surface of the mould is equipped with a negative decorative texture. Before start of application of elastomer the mould shall be - in an oven - pre-heated at the temperature reliably over the interval of melting points of the vinyl elastomer and onto its surface a separator shall be applied in a common way.

For application of the elastomer powder a common powder spraying gun operated by pressured air and controlled manually or by a robot shall be used. The powder elastomer shall be applied until the required thickness of the skin is reached. Then the mould with the applied layer shall be left to cool down to enable the withdrawal of the resulting elastomer skin off the mould. After cooling down the skin shall be removed off the mould. Thus the skin is ready to be implemented onto the finished instrument panel carrier.

Z2005/000089

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Field of the Application

The invention is determined for manufacturing of interior panels of the bodies of motor vehicles.